Electrical resistor unit



Sept. 28, 1905 R. c. ROOT 3,209,300

ELECTRICAL RESISTOR UNIT Filed May 15 1963 IN VEN TOR. 167 #1110 C E007 United States Patent 3,209,300 ELECTRICAL RESISTOR UNIT Raymond C. Root, Columbus, Nebr., assignor to Dale Electronics, Inc., Columbus, Nebr. Filed May 15, 1963, Ser. No. 280,575 4 Claims. (Cl. 338302) This invention relates to an electrical resistor and in particular to a terminal means for the resistor.

A common resistor construction includes providing resistance material around a core and connecting the resistance material to metal caps telescoped over the ends of the core. The cap having a certain thickness presents an irregularity in the surface of the core which the resistance material must pass over when it is secured to the outer surface of the cap. Thus, at the inner end of the cap where the irregularity exists, the resistance material bulges out and the connection is susceptible of being accidentally broken. Additionally and especially in wire wound resistors, connecting the ends of the resistance wire to the caps on the ends of the core causes undesirable electrical noise.

Therefore it is an object of this invention to provide an electrical resistor with resistance material having a continuously smooth outer surface.

It is a further object of this invention to provide a resistor in which the terminal plates are embedded in the ends of the core.

It is a further object of this invention to provide a resistor in which the terminal plates are confined within the core.

It is a further object of this invention to provide a resistor in which the exposed portions of the terminal plates secured to the core are flush with the adjacent core outer surface.

It is a further object of this invention to provide a resistor in which by its construction the connections between the core and the resistance material are protected against breakage.

It is a further object of this invention to provide a resistor which is silent during use.

It is a further object of this invention to provide a resistor which is strong and solid in construction.

It is a further object of this invention to provide an electrical resistor which is economical to manufacture, durable in use and refined in appearance.

These and other objects, and other features and advantages of this invention will become readily apparent upon reference to the following description when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevation view of the one form of this invention with a portion of the wire winding broken away to more clearly illustrate the end construction of the resistor;

FIG. 2 is an end elevation view of the resistor illustrated in FIG. 1;

FIG. 3 is a perspective view of the terminal plate and wire employed in the resistor shown in FIGS. 1, 2 and FIG. 4 is a perspective view of a modified terminal plate employed in the resistor shown in FIGS. 6 and 7;

FIG. 5 is a perspective view of an assembled resistor using the terminal plate of FIG. 3;

FIG. 6 is a side elevation view of one end of a resistor having a portion of the resistance wire broken away to more clearly illustrate the terminal plate of FIG. 4 embedded in the end of the resistor; and

FIG. 7 is an end elevation view of the resistor shown in FIG. 6.

The resistor of this invention is referred to generally in FIG. 1 by the reference numeral 10. This resistor comprises certain of the usual components, the core 12 around which a resistance wire 13 is wound. At each end of the resistor 10 extend terminal wires 14 which are connected by an improved terminal plate 16 to the resistance wire 13.

The cylindrical core 12 may be formed from any of the conventional core materials having the necessary electrical and molding characteristics such as a high temperature plastic like phenolic or epoxy material. Metallic wire 13 is then wound around the core along its length with each of its ends terminating adjacent one of the ends of the core. These ends are then soldered or brazed to the terminal plates 16.

In FIG. 3 the terminal plate 16 is shown which is generally U-shaped comprising a base 18 with end flanges 20. The end flanges 20 are rounded to conform to the curvature of the resistor core 12 as shown in FIG. 2. The length of the base 18 added to the thickness of each of the flanges 20 will correspond to the diameter of the core 12. Thus, a terminal plate 16 is embedded in each end of the core 12 (FIG. 1). The curved surfaces of the flanges 20 are flush with the outer round surface of the core and the ends of the flanges terminate at the outer end face of the core.

The terminal wire 14 has one end fixedly secured to the center of the outer face of the base 18 of the terminal plate 16 and consequently extends through core material 22 filling the space between the flanges 20 and the base 18.

The end portions of the resistance wire 13 are bent to extend longitudinally of the core at one of the two area-s on the core outer surface where the flanges 20 are exposed. These end portions are then soldered or brazed to the exposed outer surface of the flanges 20 (FIG. 5).

Thus it is seen that the terminal plates are integral with the core and complete destruction of the core would be necessary before they could be removed. By this construction the end portions of the resistance wire 13 do not alter the outer curvature of the resistor; a smooth circular curvature is maintained along the full length of the resistor.

In FIGS. 4, 6 and 7 a modified terminal plate 16A is illustrated embedded in the ends of a core 12A. This plate comprises only an elongated element having rounded ends 24, which as the flanges 20, conform to the curvature of the core (FIG. 7). The length of the plate is such that when it is embedded in the core its ends 24 will be flush with the outer surface of the core. With this embodiment, the only area of the plates 16A exposed through the core material are the rounded ends 24; and as seen in FIG. 6 the end portions of the resistance wire 13 are soldered or brazed to one of these plate ends on each plate.

It is obvious therefore that with either the construction in FIGS. 2, 3 and 5 or the construction in FIGS. 4, 6 and 7 that the component parts are fixedly secured together to form a very solid and strong resistor unit wherein no vibration between components will occur. And since the outer surface of the resistor is completely smooth including the areas of connection between the terminal plates and the end portions of the resistance wire, the chances of accidental breakage between any of the parts is substantially reduced.

Some changes may be made in the construction and arrangement of my electrical resistor unit without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim:

1. In a resistor comprising,

a cylindrical in cross-section, solid unitary core,

an elongated terminal plate embedded in each end of said core, each plate being disposed inwardly of the adjacent core outer end surface and extending transversely of the longitudinal axis of said core, each plate terminating in outer ends arcuate in shape to conform to the outer cylindrical core surface, whereby said outer arcuate ends are disposed in flush relationship with the outer longitudinal surface of said core to present a smooth outer surface along the length of said core,

an electrical resistance element wound around said core and having its opposite ends electrically connected to one of said arcuate ends of said terminal plates, and

a pair of electrical conductor wires embedded in said core, each of said wires being disposed along the longitudinal axis of said core, one of said wires having one end secured to one of said plates and the other of said wires having one end secured to the other of said plates, the free ends of said Wires extending outwardly of said core at a point on the longitudinal axis of said core.

2; The structure of claim 1 wherein said terminal plates having arcuate ends are further defined as each having straight sides interconnecting opposite ends and each of said plates having a width substantially less than the diameter of the core of said resistor whereby said sides of said plates are fully enclosed by material of said core to securely anchor said plates in said core.

3. The structure of claim 1 wherein said terminal plates are further defined as each having integral flange portions extending from said arcuate end portions in parallel relationship towards the adjacent end of said core, said flange portions being arcuate in cross-section to conform to the cylinder surface of said core and present a continuous smooth uninterrupted outer surface along said core.

4. The structure of claim 1 wherein said terminal plates are further defined as each having integral flange portions extending from said arcuate end portions in parallel relationship towards the adjacent end of said core, said flange portions being arcuate in cross-section to conform to the cylinder surface of said core and present a continuous smooth uninterrupted outer surface along said core, said flange portions terminating flushly in the plane of the outer end surface of said core to present a smooth flat outer end surface along the ends of said core.

References Cited by the Examiner UNITED STATES PATENTS 2,063,826 12/36 Pender 338308 X 2,559,943 7/51 Cerny 338-237 2,866,879 12/57 Cerny 338-331 FOREIGN PATENTS 107,049 4/47 Holland. 1,161,664 3/58 France.

RICHARD M. WOOD, Primary Examiner. 

1. IN A RESISTOR COMPRISING, A CYLINDRICAL IN CROSS-SECTION, SOLID UNITARY CORE, AN ELONGATED TERMINAL PLATE EMBEDDED IN EACH END OF SAID CORE, EACH PLATE BEING DISPOSED INWARDLY OF THE ADJACENT CORE OUTER END SURFACE AND EXTENDING TRANSVERSELY OF THE LONGITUDINAL AXIS OF SAID CORE, EACH PLATE TERMINATING IN OUTER ENDS ARCUATE IN SHAPE TO CONFORM TO THE OUTER CYLINDRICAL CORE SURFACE, WHEREBY SAID OUTER ARCUATE ENDS ARE DISPOSED IN FLUSH RELATIONSHIP WITH THE OUTER LONGITUDINAL SURFACE OF SAID CORE TO PRESENT A SMOOTH OUTER SURFACE ALONG THE LENGTH OF SAID CORE, AN ELECTRICAL RESISTANCE ELEMENT WOUND AROUND SAID CORE AND HAVING ITS OPPOSITE ENDS ELECTRICALLY CONNECTED TO ONE OF SAID ARCUATE ENDS OF SAID TERMINAL PLATES, AND A PAIR OF ELECTRICAL CONDUCTOR WIRES EMBEDDED IN SAID CORE, EACH OF SAID WIRES BEING DISPOSED ALONG THE LONGITUDINAL AXIS OF SAID CORE, ONE OF SAID WIRES HAVING ONE END SECURED TO ONE OF SAID PLATES AND THE OTHER OF SAID WIRES HAVING ONE END SECURED TO THE OTHER OF SAID PLATES, THE FREE ENDS OF SAID WIRES EXTENDING OUTWARDLY OF SAID CORE AT A POINT ON THE LONGITUNIDAL AXIS OF SAID CORE. 